1. Field of the Invention
The present invention relates to a wavelength-converting member using a phosphor.
2. Description of the Related Art
In a wavelength-converting member using a phosphor, light is emitted by mixing phosphor powder, for example, with a molding resin consisting of an organic or an inorganic binder resin that shields a light emitting face of a light emitting element, molding the mixture, absorbing a light emission of the light emitting element, and transforming it to a fixed wavelength. However, in a light emitting device using a light emitting diode etc., when a wavelength-converting member is constituted with a phosphor layer containing an organic binder resin, the organic binder resin itself deteriorates by light of high output in the short wavelength region (the ultraviolet region to the blue region) and there is a problem that emission brightness decreases largely by coloring, etc.
In Japanese Patent Application Laid-Open (JP-A) No. 2004-161871, it is proposed that a mixture of phosphor powder, an organic binder resin, an inorganic sintering assistant and the like is molded into a desired shape, and the organic binder resin that becomes a cause of the deterioration of the phosphor layer is sintered and removed.
In JP-A No. 2003-258308, a wavelength-converting member is proposed in which an inorganic phosphor is dispersed in a glass.
However, there is a case that sufficient weather resistance and reliability cannot be obtained in the method of sintering and removing the organic binder resin. Further, in the case of sintering at high temperature, the phosphor deteriorates or decomposes depending on the type of the phosphor, and there is a case that the emission intensity decreases.
Further, also in the case of dispersing the phosphor into a glass, the phosphor deteriorates or decomposes because the process temperature becomes high, and there is a case that the emission intensity decreases.